A data analytics team at Acme Corp is facing high compute costs due to a complex SQL query that aggregates sales data across multiple tables. Write a SQL query that optimizes the original query to minimize resource consumption while still delivering the required results.
sales (id, category_id, amount, transaction_date)
categories (id, name)
customers (id, name, signup_date)
| sales.id | sales.category_id | sales.amount | sales.transaction_date | categories.id | categories.name | customers.id | customers.name | customers.signup_date |
|---|---|---|---|---|---|---|---|---|
| 1 | 1 | 100 | 2024-01-01 | 1 | Electronics | 1 | Alice | 2023-01-01 |
| 2 | 1 | 200 | 2024-01-02 | 2 | Books | 2 | Bob | 2023-01-02 |
| 3 | 2 | 150 | 2024-01-01 | 1 | Electronics | 3 | Charlie | 2023-01-03 |
| category_name | month | total_sales | running_total |
|---|---|---|---|
| Electronics | Jan | 300 | 300 |
| Books | Jan | 200 | 200 |